A snap-action switch including a leaf spring strip reformable into two predetermined positions

ABSTRACT

There is provided a novel type of switch comprising essentially one or more tempered, deformable leaf springs rigidly attached at each end thereof to a rigid bar wherein the length of the spring is greater than the length of the bar whereby there is formed a bow in the spring. When a clamping force is applied to the bowed spring, the deformation caused thereby produces marked bowing in one portion of the spring and substantial flattening in the remaining portion. When the clamping force is reversed and applied to the bowed section, a snap-action occurs causing the previously bowed section to flatten and the previously flattened portion to bow. This reversal of deformation is very rapid and can thus be utilized as the on/off mechanism of a switch. This principle is utilized in the two principal modifications of the invention. In one modification the clamping action is applied in the form of a slide and in the other in a toggle switch.

United States Patent [72] Inventor Alfred W. Stewart 107 Boulevard,Mountain Lakes, NJ. 07046 [21 Appl. No. 800,987 [22] Filed Feb. 20, I969[45] Patented June 15, 1971 [54] A SNAP-ACTION SWITCH INCLUDING A LEAFSPRING STRIP REFORMABLE INTO TWO PREDETERMINED POSITIONS 6 Claims, 9Drawing Figs.

[52] U.S. Cl 200/67, 74/100 [51] Int. Cl ..II01h 13/48 [50] Field ofSearch 200/67, 67 D1, D2; 74/100 P [56] References Cited UNITED STATESPATENTS 2,755,352 7/1956 Birkemier ..200/67 D2 (UX) 1,973,800 9/1934Curtis ..200/67 D2 (UX) 3,050,599 8/1962 Brevick ...200/67 D2 (UX)3,109,901 11/1963 Strauss ..200/67 D2 (UX) I i 13,5s5,325

3,277,257 10/1966 Doktor ..200/67 D2 (UX) FOREIGN PATENTS 1,332,7936/1963 France ..200/67 D2 (UX) Primary ExaminerDavid Smith, Jr.Attorneys-Lerner and Behr ABSTRACT: There is provided a novel type ofswitch comprising essentially one or more tempered, deformable leafsprings rigidly attached at each end thereof to a rigid bar wherein thelength of the spring is greater than the length of the bar whereby thereis formed a bow in the spring. When a clamping force is applied to thebowed spring, the deformation caused thereby produces marked bowing inone portion of the spring and substantial flattening in the remainingportion. When the clamping force is reversed and applied to the bowedsection, a snap-action occurs causing the previously bowed section toflatten and the previously flattened portion to bow. This reversal ofdeformation is very rapid and can thus be utilized as the on/offmechanism of a switch. This principle is utilized in the two principalmodifications of the invention. In one modification the clamping actionis applied in the form of a slide and in the other in a toggle switch.

PATENTEU JUN 1 519m 3, 585, 325

INVEN'TOR. ALFRED W. STEWART LERNER a BEHR ATTORNEYS A SNAP-ACTIONSWITCH INCLUDING A LEAF SPRING STRIP REFORMABLE INTO TWO PREDETERMINEDPOSITIONS FIELD OF THE INVENTION Novel spring activated switchingmechanisms.

DESCRIPTION OF THE PRIOR ART It is known in the switching art to applythe snap-action of a deformed spring to make and break electricalcontacts. Most of these switches known in the art require rather bulkyand complex activating mechanisms in order to utilize the snap-action ofthe bowed spring. Furthermore, it should be noted that all of thesnap-action spring switches known to the prior art depend for theiraction on the complete reversal of the direction of curvature of theentire leaf spring. That is to say, a convex surface of the spring isconverted into a concave surface along the entire length of the spring.It is clear that such a mechanism requires a greater space and greaterforce for operation than one which is operative without the necessity ofentire reversal of the direction of deformation.

Among the snap-action switches known to the prior art may be includedthose disclosed in U.S. Pat. No. 2,592,357 to Trainor; in U.S. Pat. No.2,618,715 to Cataldo; in U.S. Pat. No. 2,916,575 to Mais; in U.S. Pat.No. 2,794,890 to Taylor; in U.S. Pat. No. 3,109,901 to Strauss; and inU.S. Pat. No. 2,391,238 to Hormann.

SUMMARY OF THE INVENTION In the switching mechanism of the presentinvention a leaf spring is rigidly affixed to a rigid bar in sucha'manner that the leaf spring presents a concave face to the bar towhich it isattached. It is within the contemplation of the presentinvention that more than one leaf spring may be attached to any one bar.A deforming force is then applied to the bowed leaf spring at a pointsubstantially closer to one point of attachment of the spring than tothe other. The effect of this deforming force is to cause an increase inthe degree of curvature of the longer part of the leaf and a substantialflattening of the remaining, shorter, portion of the spring causing saidshorter portion to lie close to and substantially parallel to the bar.When the deforming force is moved along the spring past the midpointthereof, a snap-action occurs, wherein the previously curved portionbecomes substantially flat and the previously flat portion becomesconsiderably bowed. This interesting snap-action property of bowed leafsprings which has been discovered herein may be utilized to make andbreak electrical contacts which are placed on and adjacent to the springleaf and the rod or bar. Examples of such switches are illustrated indetail hereinbelow.

In one modification of the invention the deforming force is applied by aslide which applies its force in the central segment of the leaf spring.By moving said slide towards one of the other ends of the leaf spring,the substantially bowed section of said spring is caused to snap andconsequently travel (like a travelling wave) from one end of said springto the other, thereby making or breaking electrical contacts. Dependingupon the design of the individual switch, it is within the scope of thepresent invention that the slide may be of insulating or conductingmaterial.

In another principal modification of the present invention, the barbearing the bowed leaf spring thereon is placed in a tube having aninternal cross section less than the maximum distance between the uppersurface of the bowed leaf spring and the bottom opposite surface of therigid rod or bar. It is preferred in this modification, however, toutilize a rod bearing a leaf spring on both sides thereof in which caseit is placed in a tube having a cross section less than the distancebetween the top of the upper bowed leaf to the bottom of the lower bowedleaf. The combination is then inserted into the tube so that the rodlies approximately on a diagonal drawn from the upper front end of thetube to the lower rear end of the tube. When the rod is rotated in'theplane in which it lies so that the front end of the rod is now at thebottom front end of the tube and the rear of the rod is at the top rearend of the tube, the bowed spring leaves reverse their location ofmaximum bowing thus giving rise to a switching action.

It is an object of the present invention to provide a contact mechanismor quick action switch.

It is a further object of this invention to provide a quick actionswitch with a plurality of contacts which will assure a proper andsimultaneous establishment or interruption of all contacts or circuitsgoverned thereby.

It is yet another object of the present invention to provide a switch ofa type referred to hereinabove of such structure and arrangement as toprovide a snap-action switch which may be operated by a slow movingactuator having a relatively short path of travel. Said actuator beingcapable of effecting instability and sudden shifting of the switchbefore it reaches neutral dead center position in which contactengagement is at lowest pressure.

DESCRIPTION OF THE DRAWINGS All drawings illustrate a cross sectionviewed perpendicularly to the plane of the leaf spring and perpendicularto the lengthwise axis of the rod or bar to which it is attached.

FIG. 1 shows a bar having attached to the upper side thereof a bowedleaf spring.

FIG. 2 illustrates the leaf spring of FIG. I wherein the said leafspring is compressed by a slide bar.

FIG. 3 shows the compressed leaf spring of FIG. 2 illustrating onemanner of attaching electrical leads and contacts to the device.

FIG. 4 shows a bar having spring leaves attached to the upper and lowerend thereof.

FIG. 5 illustrates the system of FIG. 4 having attached theretoelectrical leads and contacts as well as slide bars compressing theupper and lower leaves.

FIG. 6 shows the device of FIG. 5 with the slide bar moved across thecenter point of the device and illustrating the overcenter snap-actionthereof.

FIG. 7 illustrates the use of a device of FIG. 4 having electrical leadsand contacts attached thereto in the tube-toggle modification of theinvention.

- FIG. 8 illustrates the device of FIG. 7 in the alternately switchedposition.

FIG. 9 illustrates an end view of the device FIG. 7 taken along thearrows 9-9 thereof.

- DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventionillustrates a novel method of overcenter snap-action switching anddevices for carrying out such switching. The figures discussedhereinbelow illustrate a number of modes in which this over center snapaction can be utilized in on/off switching. It should be stressedhowever, that the combination and permutations of switching illustratedby the figures hereof merely show certain possible combinations; othercombinations will be. clear to one skilled in the art and are to beconsidered as included within the scope of the 1 present invention.

The basis of the device as shown in FIGS. 1 and 2 is a rigid bar 10constructed of electrically conductive or nonconductive material. Thereis rigidly attached to bar 10 as by fixing means 12 and 13, a bowed leafspring 11 which may similarly be of electrically conducting orelectrically nonconducting material. The choice of whether theconstructing materials are electrically conducting or nonconducting willdepend solely upon the desired circuitry of the switch constructed inaccordance with the present invention. It has been found however, thatit is preferable to manufacture the bar 10 out of nonconducting materialand the leaf spring 11 out of a tempered metal to provide the desiredmechanical properties of the device.

The leaf spring 11 is compressed by slide 22 which is preferablynonconducting so as to be independent of the electrical circuitry of theswitch.

FIG. 3 illustrates one simple modification of the device. Electricalcontacts 41 and 43 are attached to the leaf spring 11 and electricallyconnected to insulated lead wires 31 and 33. (If desired electricalcontacts 41 and 43 may be fitted into leaf spring 11 in such a manner asto be electrically insulated therefrom). In a similar manner electricalcontacts 42 and 44 are set into bar and electrically connected toinsulated electrical leads 32 and 34 respectively. Where bar 10 isconstructed of an electrically nonconductive material it is notnecessary to insulate contacts 42.and 44 from bar 10.

As illustrated in FIG. 3, and assuming a modification where contacts 41and 43 are electrically insulated from leaf 11, the device is shown in aposition giving rise to electrical contact at contacts 43 and 44 betweeninsulated leads 33 and 34 respectively and noncontact with respect tocontacts 41, 42. If slide 22 is moved towards fixing means 13, (to theposition illustrated in FIG. 2) an overcenter snap-action will occurgiving rise to electrical contact between contacts 41 and 42 andbreaking the contact between contacts 43 and 44. Of course, if desired asingle pole switch is possible with the use of only one set of contacts41, 42 or 43, 44.

The FIG. 4 shows a basic device similar to that illustrated in FIG. 1but having an additional leaf 16 connected to bar 10 by fixing means 14and 15.

An Embodiment of the device of FIG. 4 is shown in FIG. 5. In thismodification leads 31 and 33 are connected to contacts 41 and 43 in thesame manner illustrated in FIG. 3 and contacts 42 and 44 are similarlylocated on bar 10, but are electrically connected with electricallyinsulated leads 52 and 54 respectively which are passed through channelsin bar 10. Additionally into device provided with contacts 47, 48 and49, 46 and appropriate leads 57, 58 and 59, 56 respectively. Slides 22and 23 are placed in the position shown giving rise to electricalcontact between point 43 on a first curved portion of leaf 11 and point44; and point 46 on a fifth curved portion ofleaf 16 and point 49; andnoncontact with respect to point 41 on a second curved portion of leaf11 and point 42; and point 47 on a sixth curved portion of leaf 16 andpoint 48.

When slides 22 and 23 are moved towards fixing means 13 and away fromfixing means 12 and 14 to a second position, electrical contact isbroken between contact 43 on a fourth curved portion of leaf 11 andpoint 44; and contact 46 on an eighth curved portion of leaf 11 andpoint 46 and electrical contact made between contact 41 on a thirdcurved portion of leaf l1 and point 42; and contact 47 on a seventhcurved portion of leaf l6 ani point 48. It is to be understood thatslide bars 22 and 23 may operate independently if desired.

Turning to FIGS. 7 and 8 there is illustrated the toggle modification ofthe present invention. The basic unit of the modification is thearrangement of FIG. 4 having attached thereto a handle 79.

The device further comprises a housing 90 of desired external crosssection (in the modification illustrated herein, the cross section ofthe housing is circular) provided with electrical contacts 71, 72, 73and 74 are electrically connected to insulated leads 61, 62, 63 and 64respectively. Insulated electrical leads 65 and 66 are passed throughcontainer tube 90 and are electrically connected to metallic leafsprings 11 and 16 through affixing means 12 and 14 so disposed as toprovide electrical contact throughout their length. Into leaf spring 11there are set electrical contacts 81 and 82 into leaf spring 16 thereare set electrical contacts 83 and 84.

In this modification of the invention these electrical contacts aredisposed in electrical contact with the leaf springs in which they areset and not electrically insulated therefrom.

Thus, in the position illustrated in FIG. 7 there is provided electricalcontact between leads 61 and 65 through the electrical contacts 81 and71. Similarly there is provided electrical contact between leads 66 and64 through contacts 84 and 74. However, when the handle 79 is pulleddown, the device will LII rotate to the position illustrated in FIG. 8.During this rotation the leaf springs 11, and 16 will snap over centerto "break" the aforementioned contact point and at the same time make"the contact pairs 72, 82 and 73, 83.

Although this invention has been described with respect to its preferredembodiments, it should be understood that many variations andmodifications will now be obvious to those skilled in the art, and it ispreferred, therefor, that the scope of the invention be limited, not bythe specific disclosure herein, only by the appended claims.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

1. A snap switch including:

an elongated bar section having a predetermined length and first andsecond ends thereof;

a first leaf spring strip having a length greater than saidpredetermined length, said first strip being disposed on a first side ofsaid bar section and secured thereto at said first and second endsthereof; said strip tending naturally to assume a concave configurationrelative to said first side of said bar section and force applying meansapplied at a first position thereon to provide first and second curvedportions, said force applying means when applied at a second positionthereon providing a third and fourth curved portions, said first andfourth curved portions being provided adjacent to said first end of saidbar section and said second and third portions being provided adjacentto said second end of said bar section, said first and third portionsbeing shorter and lying closer than said second and fourth portionsrespectively to said bar section; and

said force applying means and said bar section slidable relative to eachother to alternately apply a force to said first and second positionsrespectively on said first strip.

2. The switch as defined in claim 1 also including:

a first contact mounted on said first strip; and

a second contact mounted on said first side of said bar section adjacentto said first contact so that said first and second contacts make andbreak continuity as said force applying means is applied to said firstand second positions of said first strip.

3. The switch as defined in claim 2 in which said force applying meansincludes:

a holding member slidable along said first strip from said firstposition to said second position on said first strip.

4. The switch as defined in claim 3 in which said first and secondpositions are disposed on opposite sides of the center of said firstleaf spring strip along said length thereof.

5. The switch as defined in claim 1 also including:

a second leaf spring strip having a length greater than saidpredetermined length, said second strip being disposed on a second sideof said bar section and secured thereto at said first and second endsthereof; said strip tending naturally to assume a concave configurationrelative to said second side of said bar section second force applyingmeans applied at a first position thereon to provide fifth and sixthcurved portions, said second force applying means when applied at asecond position thereon providing seventh and eighth curved portions,said fifth and eighth curved portions being provided adjacent to saidfirst end of said bar section and said sixth and seventh portions beingprovided adjacent to said second end of said bar section, said fifth andseventh portions being shorter and lying closer than said sixth andeighth portions respectively to said bar section; and

said second force applying means and said bar section being slidablerelative to each other to alternately apply a force, to said first andsecond positions respectively on said second strip.

6. The switch as defined in claim 5 also including:

a first contact mounted on said first strip;

a second contact mounted on said first side of said bar section adjacentto said first contact so that said first and said force applying meanscomprising a first holding member slidable along said first strip fromsaid first position to said second position on said first strip; and

said second force applying means comprising a second holding memberslidable along said second strip from said first position to said secondposition on said second position on said second strip.

1. A snap switch including: an elongated bar section having apredetermined length and first and second ends thereof; a first leafspring strip having a length greater than said predetermined length,said first strip being disposed on a first side of said bar section andsecured thereto at said first and second ends thereof; said striptending naturally to assume a concave configuration relative to saidfirst side of said bar section and force applying means applied at afirst position thereon to provide first and second curved portions, saidforce applying means when applied at a second position thereon providinga third and fourth curved portions, said first and fourth curvedportions being provided adjacent to said first end of said bar sectionand said second and third portions being provided adjacent to saidsecond end of said bar section, said first and third portions beingshorter and lying closer than said second and fourth portionsrespectively to said bar section; and said force applying means and saidbar section slidable relative to each other to alternately apply a forceto said first and second positions respectively on said first strip. 2.The switch as defined in claim 1 also including: a first contact mountedon said first strip; and a second contact mounted on said first side ofsaid bar section adjacent to said first contact so that said first andsecond contacts make and break continuity as said force applying meansis applied to said first and second positions of said first strip. 3.The switch as defined in claim 2 in which said force applying meansincludes: a holding member slidable along said first strip from saidfirst position to said second position on said first strip.
 4. Theswitch as defined in claim 3 in which said first and second positionsare disposed on opposite sides of the center of said first leaf springstrip along said length thereof.
 5. The switch as defined in claim 1also including: a second leaf spring strip having a length greater thansaid predetermined length, said second strip being disposed on a secondside of said bar section and secured thereto at said first and secondends thereof; said strip tending naturally to assume a concaveconfiguration relative to said second side of said bar section secondforce applying means applied at a first position thereon to providefifth and sixth curved portions, said second force applying means whenapplied at a second position thereon providing seventh and eighth curvedportions, said fifth and eighth curved portions being provided adjacentto said first end of said bar section and said sixth and seventhportions being provided adjacent to said second end of said bar section,said fifth and seventh portions being shorter and lying closer than saidsixth and eighth portions respectively to said bar section; and saidsecond force applying means and said bar section being slidable relativeto each other to alternately apply a force to said first and secondpositions respectively on said second strip.
 6. The switch as defined inclaim 5 also including: a first contact mounted on said first strip; asecond contact mounted on said first side of said bar section adjacentto said first contact so that said first and second contacts make andbreak continuity as said force applying means is applied to said firstand second positions on said first strip; a third contact mounted onsaid second strip; a fourth contact mounted on said second side of saidbar section adjacent to said third contact so that said third and fourthcontacts make and break continuity as said second force applying meansis applied to said first and second positions on said second strip; saidforce applying means comprising a first holding member slidable alongsaid first strip from said first position to said second position onsaid first strip; and said second force applying means comprising asecond holding member slidable along said second strip from said firstposition to said second position on said second position on said secondstrip.